The present invention relates to an antifouling structure and method effective to inhibit deposition of marine organisms such as barnacles, blue mussels and seaweed.
Offshore structures in contact with seawater are always exposed to contamination by marine organisms, resulting in damage to appearance or malfunction. For instance, ships suffer a driving force drop when many forms of oceanic organisms are deposited onto their bottoms, etc., and thermoelectric power plants are forced to stop operation when various forms of oceanic organisms are built up on their seawater intake pits, because a serious problem arises in connection with the circulation of a seawater serving as a cooling medium.
Among scores of techniques for inhibiting marine deposits studied so far in the art, there is typically now available a method for protecting an offshore structure against contamination, in which the surface of that structure in contact with seawater is coated with a coating material containing cuprous oxide or organotin.
A grave problem with this conventional method, however, is that the coating material has a service life as short as one year, since even when applied in a thick layer, it is likely to peel away. Accordingly, is needed troublesome maintenance work is necessary in which the coating material must be renewed per year.
Another method is disclosed in JP-A-60-209505 that is directed to a member for inhibiting marine deposits, which comprises copper or a copper (e.g., Cu-Ni) alloy. However, this method is found to be less than satisfactory in terms of corrosion resistance and antifouling effect.
Our years of study have now revealed that the application of a beryllium-copper alloy to an offshore structure achieves a much-more excellent antifouling effect. The reason would be that beryllium and copper ions interact synergistically, producing a great effect on inhibiting oceanic organisms from having access to the offshore structure and preventing their propagation. In other words, we have now found that the beryllium-copper alloy has a combined effect both on inhibiting marine deposits and on the continued liberation of copper ions.
A main object of the invention is to provide an antifouling structure that excels in antifouling properties and durability, dispenses with maintenance work, offers no toxicity problem, and is easy to handle.
Another object of the invention is to provide a method for fixing an antifouling structure to an application member, which enables the antifouling structure to be well fixed to the application member, excel in antifouling properties and durability, dispense with maintenance work, and present no toxicity problem.
A further object of the invention is to provide a structure for preventing deposition of organisms, which is well fixed to an application (or associated )member, excels in antifouling properties and durability, dispenses with maintenance work, and offers no toxicity problem.